<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <div id="app">

        <p>
            {{ msg | a}}
        </p>

    </div>

</body>
<script src="./vue.min.js"></script>
<script>
    Vue.filter("a",function(v){
        if(v<10){
            v = "0"+v;
        }
        return v;
    })

    var vm = new Vue({
        el:"#app",
        data:{
            msg:2,
        }
    
    })
</script>
</html>